Your question is complicated, and has many answers. There are many fine British Freemasons (Sir Winston Churchill,etc) Not all British people criticize the Freemasons. Uninformed people often criticize organizations and institutions which they do not understand. For many people, Masonry is like the Roschach test (ink blots) that you take in the psychologist’s office. You see what you want to see. Many dictators (Hitler, Franco,etc) stamped out Freemasonry in their countries.
You can learn more about it at http://www.masonicinfo.com